.\"	$OpenBSD: link_ntoa.3,v 1.2 2015/09/10 10:14:20 jmc Exp $
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.Dd $Mdocdate: September 10 2015 $
.Dt LINK_NTOA 3
.Os
.Sh NAME
.Nm link_ntoa
.Nd elementary address specification routine for link level access
.Sh SYNOPSIS
.In sys/types.h
.In sys/socket.h
.In net/if_dl.h
.Ft char *
.Fn link_ntoa "const struct sockaddr_dl *sdl"
.Sh DESCRIPTION
The
.Fn link_ntoa
function takes
a link-level
address and returns an
.Tn ASCII
string representing some of the information present,
including the link level address itself, and the interface name
or number, if present.
This facility is experimental and is
still subject to change.
.Sh RETURN VALUES
.Fn link_ntoa
always returns a NUL-terminated string.
.Sh SEE ALSO
.Xr ifconfig 8
.Sh HISTORY
The
.Fn link_ntoa
function appeared in
.Bx 4.3 Reno .
.Sh BUGS
The returned values for
.Fn link_ntoa
reside in a static memory area.
.Pp
If the
.Fa sdl_len
field of the link socket address
.Fa sdl
is 0,
.Fn link_ntoa
will not insert a colon before the interface address bytes.
